如何分别测量函数的 CPU 运行时间和挂钟运行时间，作为 Python 代码(不是来自终端)? [英] How to measure CPU running time and wall clock running time of a function, separately, as Python code (not from terminal)?

问题描述

我正在寻找一种方法来衡量 Python 中的函数性能，将挂钟和 CPU 时间分开.

I'm looking for a way to measure function performance in Python, separating wall clock and CPU time.

我研究了 python 分析器，但它们似乎旨在扫描程序而不是单独的功能.来自 http://docs.python.org/2/library/profile.html :

I've looked into the python profilers, but they seem to be designed to scan a program and not functions alone. From http://docs.python.org/2/library/profile.html :

注意分析器模块旨在为给定程序提供执行配置文件，而不是用于基准测试目的(为此，有时间以获得合理准确的结果).这尤其适用于针对 C 代码对 Python 代码进行基准测试:分析器会为 Python 代码引入开销，但不会为 C 级函数引入开销，因此 C 代码似乎比任何 Python 代码都快.

Note The profiler modules are designed to provide an execution profile for a given program, not for benchmarking purposes (for that, there is timeit for reasonably accurate results). This particularly applies to benchmarking Python code against C code: the profilers introduce overhead for Python code, but not for C-level functions, and so the C code would seem faster than any Python one.

然后我尝试了 timeit 模块:http://docs.python.org/2/library/timeit.html ，但它似乎不支持 CPU 和挂钟时间的分离.据我了解，它只是衡量总运行时间.

I then tried the timeit module: http://docs.python.org/2/library/timeit.html , but it doesn't seem to support separation of CPU and wall clock time. As I understand, it just measures total run time.

我正在寻找的是这样的:

What I'm looking for is something like this:

$ time python yourprogram.py

real    0m1.028s
user    0m0.001s
sys     0m0.003s

但不是从命令行调用它，我需要从 python 代码调用它.

But instead of calling it from command line, I need to call it from python code.

类似于 R 中的 system.time():

Something like system.time() in R:

print(system.time(replicate(repeats, factorialRecursive(150))))
 user  system elapsed 
0.041   0.001   0.041 

我如何在 Python 中实现这一点?

How can I achieve this in Python?

推荐答案

resource 模块 包含 getrusage，它应该允许您分别检索用户、系统和挂钟时间，就像 time命令执行.

The resource module houses getrusage, which should allow you to retrieve user, system, and wall-clock time separately, just as the time command does.

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